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97 Cards in this Set
- Front
- Back
When do alkenes NOT have cis trans isomerism? |
When either carbon in the double bond is attached to 2 of the same groups |
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What is Z geometry? |
Higher ranked groups on same side of the double bond |
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What is E geometry? |
Higher ranked groups on opposite sides of double bond |
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What kind of alkene is more stable? |
More substituted |
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What is hyperconjugation? |
Electrons in neighbouring sigma orbitals stabilize vacant antibonding pi orbitals |
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What is an antibonding orbital? |
Unfilled orbitals resembling p orbitals, carrying partial positive charge due to lack of electrons |
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What does regiospecific mean? |
Reaction where only one orientation of product occurs |
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What are inductive effects? |
Shifting of electrons in sigma bonds in response to electronegativity of nearby atoms, stabilizing the vacant p orbital |
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___ reactions have transition states that structurally resemble a ___. |
- exergonic; reactant - endergonic; product |
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What is dehydrohalogenation? |
Loss of HX from an alkyl halide to form a multiple bond |
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What reagents are used in dehydrohalogenation? |
KOH in ethyl alcohol |
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What is dehydration? |
Loss of water from an alcohol to form a multiple bond |
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What reagents are used in dehydration? |
H2SO4 and H2O in THF |
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What is halogenation? |
Addition of X2 to form 1,2-dihalides |
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What kind of stereochemistry results from halogenation? |
Anti |
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What is addition of HOX? |
Creation of a halohydrin (1,2-halo alcohol) |
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What are reagents used to make halohydrins? |
Br2 or Cl2 in water |
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What reagents are used to create a bromohydrin? |
NBS in DMSO |
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What is reduction? |
Reaction that results in gain of electron density for carbon |
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What can cause reduction? |
- formation of bond between carbon and less electronegative atom - bond breaking between carbon and a more electronegative atom |
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What is hydrogenation? |
Addition of hydrogen to a multiple bond to yield a saturated product |
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What stereochemistry does hydrogenation occur with? |
Syn |
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What reagent is used in hydrogenation? |
H2 with Pd/C or PtO2 |
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What is oxidation? |
Reaction that results in a loss of electron density for carbon |
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What can cause oxidation? |
- bond formation between carbon and more electronegative atom - bond breaking between carbon and less electronegative atom |
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What is an epoxide? |
Cyclic ether with an oxygen atom in a three member ring |
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Alkenes oxidize to give epoxides on treatment with ____ |
Peroxyacid |
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Treating a base with halohydrin leads to ____ |
Elimination of HX and production of an epoxide |
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What happens when epoxides are treated with hydronium? |
Opening of the epoxide and creation of a 1,2-diol (glycol) |
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What is the name for two step epoxidation/hydrolysis? |
Hydroxylation |
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How can hydroxylation be carried out directly? |
Treatment with osmium tetroxide followed by cleaving with aqueous sodium bisulphate |
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What cooxidant is used with osmium tetroxide? |
NMO |
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What solvent is used with osmium tetroxide? |
Acetone and water |
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What stereochemistry does the hydroxylation with osmium tetroxide produce? |
Syn |
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When ozone adds to a C=C bond, what forms? |
Molozonide |
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What does molozonide rearrange to form? |
Ozonide |
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What is produced when ozonides are treated with a reducing agent? |
Carbonyl compounds |
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What do oxidizing reagents other than ozone do? |
Double bond cleavage |
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KMnO4 can produce carboxylic acids if _____ |
Hydrogens are present on the double bond |
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What is carbene? |
Neutral molecule containing a equivalent carbon with 6 electrons in its valence shell; R2C |
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Alkene addition with a carbene yields ____ |
Cyclopropane |
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What does stereospecific mean? |
Only a single stereoisomer is formed as a product |
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What is the Simmons-Smith reaction? |
Method for preparing nonhalogenated cyclopropanes, involving a carbenoid instead of a carbene |
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What reagents are used in the Simmons Smith reaction? |
Diiodomethane with zinc copper alloy |
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What are simple alkene polymers called? |
Chain growth polymers |
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How do alkenes react to form polymers? |
Reaction with radical catalysts to undergo radical polymerization |
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What type of radical is more stable? |
More substituted |
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What happens during propagation in polymerization? |
Radical from initiation adds to alkene to generate alkene derived radical, forming polymer chain |
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What happens during termination of polymerization? |
Two radical chains combine |
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What is an oxymercuration intermediate? |
Reaction initiated by electrophilic addition of Hg2+ ion to alkene, corresponding to Markovnikov addition |
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What is hydroboration? |
Addition of borage to an alkene to yield an organoborane intermediate, does not follow Markovnikov addition |
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What reagents are involved in hydroboration? |
BH3 in THF |
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What happens when hydrogen peroxide and hydroxide ions react with an organoborane intermediate? |
BH2 replaced with OH |
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Treatment of a 1,2-dihaloalkane with _____ produces twofold elimination of HX |
KOH or NaOH |
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What is a vinylic substituent? |
Attached to a double bond carbon |
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Vinylic halides give alkynes when treated with ___ |
Strong base |
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What reagents are used in addition of X2 to an alkyne? |
Dihalide and dichloromethane |
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What is mercury (ii) catalyzed hydration of alkynes? |
Hydration reaction with Markovnikov orientation resulting in an enol |
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What kind of reaction converts terminal alkynes to methyl ketones? |
Mercury II catalyzed hydration |
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What is keto enol tautomerism? |
Proton can travel from OH down a double bond to form a ketone and CH3 |
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What is a tautomer? |
Isomeric compound that can rapidly interconvert by movement of protons |
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What is hydroboration oxidation of alkynes? |
Borane adds to alkynes giving vinylic borane in non Markovnikov orientation, and oxidation with H2O2 produces an enol |
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How can you get complete reduction of an alkyne to an alkane? |
Addition of H2 with Pd/C |
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How can you produce a cis alkene from an alkyne? |
Hydrogenation with Lindlar catalyst |
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How can you produce a trans alkene from an alkyne? |
Hydrogenation using Na or Li in liquid ammonia |
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What is oxidative cleavage? |
Cutting a multiple bond and forming carbonyl compounds |
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What reagents can be used to cleave internal alkynes? |
KMnO4 or O3 |
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What are the products formed from cleavage of a terminal alkyne? |
A carboxylic acid and CO2 |
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Reaction of a strong base with a terminal alkyne results in ____ |
Removal of the terminal protons and formation of an acetylide anion |
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What is alkylation of acetylide anions? |
Acetyl anions react with alkyl halides, yielding new alkyne product |
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How can terminal alkynes be prepared? |
Alkylation of acetylene |
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Define organohalide. |
Organic compound containing at least one halogen atom |
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Define alkyl halide |
Halogen atom bonded to a saturated carbon |
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As you go down the periodic table, what trends are seen in C-X bonds? |
Bond lengths increase and bond strengths decrase |
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What is allylic bromination? |
Alkenes react with NBS in the presence of light to produce alkyl halides |
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What is the allylic position? |
Bonded to an atom bonded to a double bond carbon |
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What is the most stable radical? What is the least stable? |
Most is allylic, least is vinylic |
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What is delocalization? |
Allyl radicals can move on the compound and can cause a mixture of products |
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What is the simplest method of deriving alkyl halides? |
Treating alcohol with HCl HBr or HI |
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What do you use to convert primary/secondary alcohols into a chloro halide? |
Thionyl chloride |
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What do you use to convert primary/secondary alcohols into a bromo halide? |
Phosphorus tribromide PBr3 |
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What do you use to convert primary/secondary alcohols into a fluoro halide? |
HF in pyridine |
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What solvent do you use when preparing alkyl halides from alcohols? |
Ether or pyridine |
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What is a Grignard reagent? |
RMgX |
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What reagents are used to create a Grignard reagent? |
Mg in ether or THF |
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What is Gilman reagent? |
LiR2Cu |
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What is a Suzuki-Miyaura reaction? |
Coupling reaction for joining aromatic rings |
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What does Sn2 stand for? |
Substitution nucleophilic bimolecular |
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What is the reaction rate in an Sn2 reaction? |
Rate of disappearance of reactant (k[RX][OH-]) |
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What increases the rate of an Sn2 reaction? |
- lowering energy of transition state - having a more unhindered substrate |
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Sn2 reactions do not occur for ___ and ___ halides. |
Vinylic and aryl |
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What is a nucleophile? |
Neutral or negatively charged Lewis base |
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What are some trends seen in nucleophiles? |
- negative charge generally more reactive than neutral - increases with downward progression in periodic table - roughly parallels basicity |
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What are the best leaving groups? |
Groups that can most stably hold a negative charge |
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___ bases are good leaving groups and ___ bases are poor leaving groups. |
Weak, strong |
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What are characteristics of a good solvent for Sn2 reactions? |
Polar and aprotic |
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What happens to an Sn2 reaction if a solvent is protic? |
Hydrogen bonding between the solvent and electrophile resulting in reduced reactivity |